Drop Down arrows are missing on iPhone and iPad

The drop-down functionality will still work by clicking the field although there is no arrow down.

It seems like this is a known issue with Apple devices wherein the drop-down arrow will disappear if you put a CSS style background image in the <select> element. Here’s a solution, please try to inject this custom CSS.

#input_11, #input_13 {
-webkit-appearance: menulist;

Unfortunately, the drop-down arrow will appear but the background will not show up. Hope this helps. Thank you.

Reference: https://www.jotform.com/answers/587658-Drop-Down-arrows-are-missing-on-Iphone-and-Ipad

Thanks to JAN who is commented answer